Upvote:2
Some online banks provide the solutions you need, like WeSwap or Revolut : For less than $10, you can get a Mastercard, top it up in your local currency and spend it in (almost) any foreign currencies.
I have one of them and I already bought a SNCF train ticket with it (and also some flight tickets in EU), I never get any trouble.
Upvote:2
Not really an answer, but I thought I'd comment on what I ended up doing:
Upvote:5
I have never had a problem using my Schwab visa on websites for Renfe (Spanish trains) or airlines based in Spain, Turkey, and elsewhere. Nor for any hotels. Never tried SNCF. I did use it to buy a train ticket on loco2.com which should also be able to book SNCF.
Schwab is one of several banks that charges no exchange fee. They use whatever rate Visa uses, which is a hair higher than transferwise. Many sites also accept PayPal, which lets you choose the currency but not at a great rate.